designed a special olive head drill for veterinary surgeon Dr Ian Griggs to meet a specific requirement for a surgical procedure that was needed to repair a bone fracture.
Dr Griggs developed the Echidna Pin following a fracture to his clavicle (collar bone), which is one of the most commonly fractured bones. The pin is a device that is inserted into the hollow of the bone and positioned across the fracture in order to align the two ends and allow the bone to mend. Small nails are extended from within and perpendicular to the device at either end of the pin, which penetrate into the bone and hold it firmly against the forces acting on the fracture.
Many problems were faced when developing the surgical technique to gain access to the fracture and insert the pin, which would essentially form the brace. The challenges included locating and drilling an entry point into the bone with minimal damage to surrounding tissue, and secondly, hollowing out the soft marrow from inside the bone to allow room for the location of the pin.
Essentially to repair a fracture, the device has to be located into the hollow middle (marrow) of the bone, called the medulla. Because of the clavicle’s S-shape, access can be gained into the medulla from the flexure of the bone just behind the shoulder, which would require a suitable drill tool.
Dr Griggs contacted Geoff Frost from Sutton Tools’ special tool department and discussed the application. A standard 6.5mm drill was manufactured in stainless steel, with some markings located along the shank to aid in determining the depth drilled.
Though the drill created a suitable channel within the bone, it also caused excessive damage to the surrounding tissues. Dr Griggs went back to Sutton Tools to report his issues with the first trial, and further modifications to the drills were discussed.
Key considerations included stainless steel construction, an olive shaped drill head of 6.5mm maximum diameter on the end of a 4.0mm shank with the whole tool to be cannulated with a 2.0mm channel running along the length of the drill.
A guide wire could first be placed into position along the required path for the drill to follow, and the channel could then be accurately drilled into the bone with a stopper at the end of the guide wire preventing the drill from going too deep.
The final design kept the drilling surface quite small with the drill passing very quickly through the surrounding tissues, limiting the damage to these tissues. The smaller diameter shank would cause minimal disruption.
The next trial for the new olive drill design delivered great results with the drill performing superbly, but the surgeon had some difficulty inserting the Echidna Pin, which was due to the drilled out hollow not being straight enough. It was felt that the olive head was too short and tended to follow the irregular surface inside the medulla, which is not always in a perfectly straight line.
It was decided to lengthen or elongate the olive head to 25mm in the hope the canal would be drilled along a straight axis. A further trial conducted using an upgraded pin and the new drill proved a success as there was no evidence of extra effort needed by the surgeon to place the device. A trial was conducted at the Victorian Institute of Forensic Medicine to examine the use of the Echidna Pin as a method for the repair of a fractured clavicle, and to refine the technique for its insertion and removal.
The olive drill is still under development with further improvements in the pipeline for the evolution of the tool for use in the repair of fractures to the collar bone. The olive drill is just another example of how Sutton Tools works with the medical industry to develop specialised cutting tools for surgical procedures.